Autism spectrum disorders are a group of complex brain-based developmental disorders that are often characterised by challenges in social interaction, difficulties in both verbal and non-verbal communication, as well as restricted repetitive behaviours and interests.

Autism is a relatively prevalent disorder that affects over tens of millions of individuals across the globe, to varying degrees. In Singapore, it is estimated that more than 50,000 individuals suffer from autism. This figure makes up roughly 1% of the republic’s population.

Although this complicated disorder has been around since several decades ago, the causes behind it were largely unknown. Through the years, many researchers and scientists have attempted to explain the risk factors contributing to the onset of autism spectrum disorders – including a popular conjecture in the 1990s which implied that vaccination could be a leading cause. While such false conjectures may have been disproven with further in-depth research, the causes of autism continue to elude researchers worldwide.

With the aid of evolving technologies, new research studies have emerged that highlight the link between genetics and autism spectrum disorders.

Changes in micro-RNAs also linked to autism

Researchers from UCLA have also discovered new evidence that the brains of individuals diagnosed with autism have distinctive changes in the levels of micro-RNAs. Micro-RNAs are tiny regulator molecules made of single-stranded RNA (ribonucleic acid), which have the function of controlling the activities of large gene networks.

In the study, the researchers measured levels of nearly 700 micro-RNAs in samples of brain tissue obtained from both individuals with autism and individuals without autism. The analysis found that the samples from most of the autism cases indicated a distinctive “signature” of abnormalities which involved 58 micro-RNAs.

“These findings add a new layer to our understanding of the molecular changes that occur in the brains of patients with autism spectrum disorders, and give us a good framework for more detailed investigations of microRNAs' contributions to these disorders," said Dr Daniel Geschwind, principal investigator of the research study.

2,500 genes could be related to autism

At the same time, another group of researchers from Princeton University and the Simons Foundation in New York City have now developed a machine-learning program that could potentially uncover the origins of autism within human DNA. This program has helped the researchers in gathering a gene pool that would enable them to better pin-point the genes that might be potential causes of autism.

This program, the very first of its kind in the world, is equipped with the ability to efficiently analyse over 100 million gene interactions. It provides researchers with an easier way of picking out gene interactions which might correspond to autism. So far, the program has effectively identified 2,500 genes which might be potential causes of autism spectrum disorders.

Co-lead author Dr Arjun Krishnan commented, “Geneticists can now focus on the top-ranked autism-risk gene predictions from our machine-learning program, both to direct future genome sequencing studies and to prioritise individual genes for experimental studies.”

If the gene predictions hold true, this study will certainly enable future researchers to delve deeper into the underlying causes of autism, and derive more effective treatments for this developmental disorder.

Other environmental factors that may influence autism

Researchers have also uncovered a link between the use of ultrasounds and autism severity. For instance, a study by researchers at UW Medicine, UW Bothell and Seattle Children's Research Institute revealed that exposure to diagnostic ultrasound in the first trimester could be linked to more severe autism symptoms.

Zinc is yet another environmental factor that may potentially influence autism spectrum disorders. Recent research conducted at the University of Auckland has indicated that cellular changes in the brain caused by autism-linked genetic mutations could potentially be reversed by zinc.

The study found that individuals diagnosed with autism typically suffer from zinc deficiency. Further research in this area could shine light on possible ways to reverse cellular deficits caused by autism-associated changes in brain cells. MIMS


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